📖 update Azure quick start for CAPZ v1.16

[nojnhuh]

What this PR does / why we need it:

This change updates the Azure parts of the quick start guide to account for the default auth mechanism in templates changing to Workload Identity in CAPZ v1.16 (coming next week). These changes add steps to change back to Service Principal auth to avoid turning this doc into yet-another-Workload-Identity-setup doc and to continue to support CAPZ v1.15.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes kubernetes-sigs/cluster-api-provider-azure#4921

/area documentation
/area provider/azure

[nojnhuh]

We'd also like to have this in the latest release branch so it's live when we release CAPZ v1.16 next week. No need to wait until before then to merge though.

/cherry-pick release-1.7

[k8s-infra-cherrypick-robot]

@nojnhuh: once the present PR merges, I will cherry-pick it on top of release-1.7 in a new PR and assign it to you.

In response to this:

We'd also like to have this in the latest release branch so it's live when we release CAPZ v1.16 next week. No need to wait until before then to merge though.

/cherry-pick release-1.7

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[nojnhuh]

/assign @jackfrancis

[jackfrancis]

/lgtm

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 6bf0f1316704c63a4881365d490ca3d7d45a8941

[sbueringer]

Nice, thx!

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: sbueringer

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[k8s-infra-cherrypick-robot]

@nojnhuh: new pull request created: #10859

In response to this:

We'd also like to have this in the latest release branch so it's live when we release CAPZ v1.16 next week. No need to wait until before then to merge though.

/cherry-pick release-1.7

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.